Sea Urchin
Gamete collection

Spawning
can be induced in adult sea
urchinsby injecting 1 ml of
a0.5M KCl solution into
several sites in the soft
membrane around the mouth. Within minutes, the gametes
should appear: the sperm are
off-white, the eggs are tan to orange. Collect the sperm by
inverting the male onto a
small, dry petri dish. After several minutes, cover the
sperm and put on ice. Collect
the eggs by inverting the female onto a small beaker filled
with ASW
(room temperature for L.
variegatus, and below 14ºC for S.purpuratus and
L.pictus ). Keep urchins from falling in
with aluminum foil supports.
Allow eggs to settle, pour off ASW and replace with fresh
ASW (at same temperature).

Colletion of sperm (left) and
eggs (right) from L. variegatus

The sperm can be transfered to a small
tube and stored at 4° C for up to 2 weeks. Eggs should
normally be used on the same day as they are collected.
Consult the Sea
Urchin Embryology web site for
a protocol for collecting the eggs with antibiotics, which
allows them to be stored for several weeks before use. Check
to see if the population contains a large percentage of
immature eggs; they will not fertilize.